pencil lead refill

I put lead in the mechanical pencil.

私は芯繰り出し式鉛筆に替え芯を入れます

I put lead in the mechanical pencil before I start studying.

私は勉強を始める前に芯繰り出し式鉛筆に替え芯を入れます

I put lead in the mechanical pencil in my room before I start studying.

私は勉強を始める前に自分の部屋で芯繰り出し式鉛筆に替え芯を入れます

I put lead in the new mechanical pencil in my room before I start studying.

私は勉強を始める前に自分の部屋で新しい芯繰り出し式鉛筆に替え芯を入れます

I put thin lead in the new mechanical pencil in my room before I start studying.

私は勉強を始める前に自分の部屋で新しい芯繰り出し式鉛筆に細い替え芯を入れます